Weighing and filling machine



g- 1954 c. F. CARTER WEIGHING AND FILLING MACHINE Filed April 1, 1952 5Sheets-Sheet l 4 T TORNEYS INVEN TOR. BY flalmcelfirler Aug. 24, 1954 c.F. CARTER 2,687,271

WEIGHING AND FILLING MACHINE Filed April 1, 1952 5 SheetSP-Sheet 2 o I Ka 8 '7 "WI [I I/ I I I "III" II-IIIIIIIIIIIIIII-I IIIIUII/IJMIHINVENTOR.

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A TTUR/VE'YS Aug. 24, 1954 c CARTER 2,687,271

WEIGHING AND FILLING MACHINE Filed April 1, 1952 5 Sheets-Sheet 3 ATTORNE Y5 Aug. 24, 1954 c CARTER 2,687,271

WEIGHING AND FILLING MACHINE Filed April 1, 1952 5 Sheets-Sheet 4 ZilATTOE/YEYS Aug. 24, 1954 c. F. CARTER mncnmc AND FILLING means 5Sheds-Sheet 5 Filed April 1, 1952 STATION-1 3 m m a Mlua. I M 0 3 I j mm M u Lrm I N V EN TOR. llamel'lkrlsr u,

Patented Aug. 24, 1954 UNITED STATES. PATENT OFFICE WEIGHING AND FILLINGMACHINE Clarence F. Carter, Danville, 111.

Application April 1, 1952, Serial No. 279,889

3 Claims. 1

This invention relates to an automatic machine for weighing fine powdersand vacuum filling of containers.

It is an object to automatically weigh powders with substantialaccuracy, and to deliver them by vacuum methods to bags, boxes, cartonsand the like, particularly containers holding -100 pounds of powder.

It is a further object to de-aerate the powders before delivery to thecontainer, so as to eliminate objectionable outage therein after thecontents have settled.

Figure 1 is an elevation of a machine designed to accomplish thesepurposes.

Figure 2 is a sectional elevation of a hopper and valving mechanismshown diagrammatically in Figure 1.

Figure 3 is a plan view in section along the lines 3-3 of Figure 2.

.Flgure 4 is a plan view of the machine alon lines 4-4 of Figure 1.

Figure 5 is an elevation in partial section of one of the shroudelements of the machine, with a bag in filling position.

Figure 6 is an end view in section along lines 8-! of Figure 5.

Figure 7 is an elevation in partial section of a modification using adifferent type shroud and filling spout which may be used in place ofthose 7 shown in Figure 1, one being in filling position age hopper ofany conventional design. At the bottom of the hopper is a valve 2,connected by way of flexible coupling 3, to a first gross-weight hopper4. Valve 2 is of the type generally designatedAinFigure 2. Alinel.inthetopof the hopper, leads to a source of vacuum and to atmosphericrelief, through an arrangement generally designated as C in Figure 2.The hopper is suspended on a balance arm 6, by means of the knifeedge 1. The lever actuates a conventional weighing scale 8. 0n the scaledial is a contact point 9, which may be contacted by the indicator handI. to close an electrical circuit not shown, thereby operating asolenoid valve and causing valve 2 to close, as hereinafter more fullyspace between wall 30 and liner ll.

2 explained. The contact 9 may be made adjustable by known means tocorrespond to any desired weight of material. At the bottom of hopper 4is a second valve ll of the type shown at A. A second flexibleconnection I2 joins the outlet of the valve with duct ll, which leads toa flexible connection It opening into weighing hopper l5. This hopperalso is mounted by knife edge ii, on arm l1. This actuates a scale 18similar to scale I, equipped with a contact point I8, which actuatesthrough appropriate electrical connections a solenoid valve whichoperates to cause valve ii to close. The vacuum-relief line is is of theconstruction shown at C. At the outlet of the hopper is a valve 20, ofthe type designated B on Figure 2. A flexible connection 2! leads tofinal weighing hopper 22. This is mounted on the knife edge 22 and arm24. A scale 25 is actuated by arm 24, has two contact points, one at 28and one at 21, which may be contacted by pointer 25' to actuate solenoidvalves controlling valve 20. Mounted on the bottom of the hopper is avalve 28, of the type designated A. A flexible connection 29 joins thehopper to a line discharging into a container as hereinafter describedin greater detail.

Figure 2 is an elevation in section of hopper 22, showing details of theconstruction of valves A. B and C. as well as details of the internalhopper structure. Hoppers I and I5 are of similar construction. Thehopper comprises an outer wall 30 of any suitable material such as sheetmetal. The hopper is lined with a flexible material such as rubber,either synthetic or natural, the liner being designated 2|. At the lowerend, the liner is turned back over the end of the sheet metal hopperwall, and is held in place by flange 32 attached to, the hopper andflange 23 attached to valve A. A channel 24 extends around the top ofthe hopper, and the liner ii is turned back over the inside edge thereofand is held in place by the hopper lid 35 when it is clamped or boltedin place. Lying between the liner 3i and the outer wall 30 is aplurality of rubber tubes 38. These are sealed at their lower ends, andare held in position at. the upper end by being turned back over thechannel and held in place by the hopper top 35. These tubes are spacedapart as shown, the distance generally being of the order of 0.5-1 inch.Since the amount of surface at the upper end of the tapered hopper isgreater than at the lower end, some of the tubes are necessarily shorterthan others. An air-vacuum line 21 leads into the This is conthe hopper.

nected to the atmosphere and to a source of vacuum not shown, through athree-way valve not shown, whereby the space between the wall 30 and theliner 3| may be alternately evacuated and relieved to the air. Since thetubes 36 are sealed and contain air, the flexible liner 3| will assumethe position shown in Figure 3 when the space is evacuated, but uponrelief of the air, the liner will return to its normal position. Byrapidly alternating between vacuum and relief during the time the hopperis being filled and emptied, the liner is caused to vibrate and thusdislodge the powder that may be in the hopper, causing it to flow freelyand quickly out of the hopper without substantial holdup. This actionalso assists in de-aerating the powder within The valve designated A isattached to hopper 22 by means of flanges 32 and 33. The body of thevalve 38 is generally cylindrical. A flexible connection 29 is mountedby means of flange 39 to the exterior of the valve. The flexibleconnection is attached to flange 40. An air-vacuum line 4| extendsthrough a compression fitting 42 to a T, 43, which is plugged at 44.Extending downwardly from the T is a tube 45, perforated at 46. Aroundthe tube and covering the perforations is a rubber sleeve 41. Tube 45 isplugged at 48. The sleeve 41 is attached at each of its 1 endsto tube45, and when air pressure is .ap-

plied through line 4|, assumes the position.

shown, thus completely closing the passage through the valve. Line 4|leads to a three-way valve which connects to a source of air pressureand to a vacuum supply. When vacuum is applied to line 4|, tube 41assumes the position shown in the drawing. It is important that vacuumbe applied, since otherwise the sleeve 41 may not resume its normalposition but may wrinkle. Upon application of the vacuum, asubstantially unobstructed annular passage is formed.

Hopper I5 is connected to the valve generally designated B, by means offlanges 50 and 5|. This valve has three sections 52, 53 and 54, whichare generally cylindrical. A rubber liner 55 is held terminally insection 53 by being pinched between flanges 56 and 51, and 58 and 59.This rubber liner may be beaded at the ends.

Inside the cylindrical-body is a smaller tube 60, which is supported bymeans of spider 6| or other suitable means. A relatively large, annularpassageway is formed between tube 53 and liner 55. An air-vacuum line 62extends through an appropriate compression fitting 63 to T 64, which isplugged at 65. Extending downwardly therefrom is a small tube 66, whichis perforated at 61. This tube is plugged at the lower end. A rubbersleeve 68 is attached, as was described in connection with valve A, totube 66. The liner 55 is inflated by applying air pressure to airvacuumline 69, which extends through the wall of the section 53,'throughcompression fitting 10. Upon being inflated, the liner 55 assumes theposition shown by the dotted line. In a similar manner, by applying airto line 62, the liner 68 may be inflated to close the passageway betweentube 69 and the liner 68.

Cover plate is provided with an opening 1|, which is covered by a screen12 mounted by any convenient means, such as bracket 13. Correspondingwith the opening 1| is an outlet tube 14, which may be attached to the T15, one arm 16 of which leads to a source of vacuum, and the other arm11 leads to the atmosphere. Mounted within lines 16 and 11 are twovalves 18 and 19, of the type described in greater detail in connectionwith valve A. From these lead the lines and 8|, connecting with athree-way valve or cook 82. This valve connects by way of line 83 to asource of compressed air. Through shell of cook 82 is an opening 80',and a line 8| leading to line 16. A groove 82 affords communicationbetween lines 8| and 8| when the cock is in the position shown, todeflate valve 19. When the cock is turned 90 clockwise, valve 18 isrelieved through line 80, groove 82' and opening 80'.

Refer to Figure 5. Flange 40 is designed to coincide with flange 84 insealing relationship. Flange 40 is forced against flange 84 and sealingrubber 85 by applying air pressure to air cylinder 86, the piston ofwhich strikes bracket 81, forcing the two flanges into sealingrelationship. This is done after hopper 22 has been filled and thecontents are to be drawn into the container.

Leading from flange 84 is the filling tube or head 88. This extendsthrough the top of a split shroud 89, which, when closed completely,surrounds a container such as bag 90. The bag shown is of themultiwalled type, which is sealed or sewed before filling and which isfilled through a small opening left in one corner for introduction ofthe filling spout 9|. This opening is closed after the filling operationis complete, by a flap 92, which automatically covers the opening whenthe contents of the bag rest against it. Such bags are of familiardesign and form no part of this invention. The shroud 89 is made up intwo sections, and may be of the type shown in Figures 1, 4, 5 and 6, ormay be of the type shown in Figures 7 to 10. These sections, whenclosed, form a vacuum-tight receptacle surrounding the bag, asshown inFigures 5 and 6. One section of .the split shroud is stationary, and ismade up of wall 93, bottom 94, top section 95, and wall 96. The other,movable section is made up of top section 91 and walls 98 and 99. At allpoints of contact between the movable and the stationary sections is aresilient washer or sealing member such as shown at I00, to insure agas-tight seal. On the movable section is mounted a bracket IN, to whichis pivotally attached the piston I02 of an air cylinder whereby themovable section can be moved away from and upwardly from the stationarysection to the position shown in the dotted lines in Figure 6 and inplan view in the representations of the two open shrouds on therighthand side of Figure 4. In plan view, the closed shouds areillustrated by the two shrouds on the lefthand side of Figure 4. Sincethe split shrouds and the mechanism for opening and closing them areidentical, the same reference numerals are employed. The air cylinderI03 is pivotally mounted on a frame I04, which is attached to the mainframe of the machine. A pair of upper guide tracks I05, I05, and acorresponding pair of lower guide tracks I06, I06 (best seen in Figurel), are mounted on frame I04 and are attached to a frame I01, I01, onwhich the stationary member of the split shroud is rigidly mounted.These guide tracks slope upwardly and away from the stationary member ofthe split shroud.

Mounted on the movable member of the shroud is a bracket I08, supportingrollers I09, which follow the guides I05 and I06 when the movableportion of the shroud is retracted by the air cylinder I 03 and itspiston I02. The air cylinders are of conventional design and need not beexplained in detail. The manner of opening the shroud by swinging themovable portion outwardly and upwardly, permits ready placement of thebag on the filling nozzle 3| and removal of the filled bag from theshroud. The bag is removed from the shroud by operation of an aircylinder 1 ll, which is mounted on wall 93 of the stationary member ofthe shroud and which has a platen III attached to piston II2 of the aircylinder. when the shroud is open, as shown in the upper righthandcorner of Figure 4, the platen Ill thrusts the bag outwardly and oil! ofthe floor 34 of the stationary member of the shroud. An empty bag isthen placed in position as shown by Figure 5, by slipping the opening atthe valve end over the nozzle 3|.

Mounted on wall 96 of the stationary member is a three-way valve 3,which leads to a source of vacuum attached to line II4 when the valve isin the position shown and when the shroud is closed for filling. Thethree-way valve has a port II5 open to the atmosphere. Communication tothe interior of the shroud is made through port H6.

The filling spout 3| may be equipped with a sealing device to preventpassage of powder from the interior of the bag into the shroud duringthe filling operation. In this case a section of extra heavy pipe II! isprovided. A portion of the pipe is cut away at I I8, and over this isplaced a grid or screen I I9. A rubber sleeve I20 is placed over andsupported by the grid. The sleeve is preferably a section of thin-walledrubber tubing, which is attached at either end to the pipe, and whichfits substantially fiush with the outside of the pipe section III. Thisleaves an annular space around a part of the length of the pipe I II,which serves as an air pocket. When the interior of the shroud isevacuated duringthe filling operation, the thin-walled tubing I20 iscaused to expand into the position shown by the dotted lines, due toexpansion of the air within this annular space. The expanded tube I20thus presses against the end of the bag and the closure flap 92sufiiciently to prevent dust from escaping from between the fillingspout and the bag into the shroud. Since the rubber tube I20 issubstantially flush with the outside of pipe III, it oifers noimpediment to the bag bein placed over the spout.

The apparatus can .be operated as a singlehead unit, or a plurality ofthe shroud elements can be mounted on a rotatable dial, as shown inFigures 1 and 4, for a more rapid filling operation. In this case, theunit is mounted on a stationary base I2I, supporting a vertical pipeI22, over which is a rotatable pipe I23 to whichis rigidly attached arotatable dial or platform I24, supported by a web I25. The supportinframes IIII for the stationary portion of the split shrouds are rigidlyattached to dial I24. The dial is rotated by any suitable means, such asmotor I26, speed reducer I21, and Geneva movement I28. These are allwell known mechanical devices and need not be described in detail.Mounted above the Geneva movement is a conventional rotary air valve,generally indicated at I38. This supplies air to the air cylinders whichopen and close the shrouds and eject the filled bags, and is designed totime their operation at the appropriate stations. The rotary valve andtiming means are not per se a part of the invention, since any suitablemeans may be used. The lower member I3I is stationary, and the uppermember I32 revolves with the member I23. Air inlets I33, and air outletsI34, are provided. Air passes through 6 grooves (not shown) in the faceof member I3I. These coincide with the ports I34, so that air issupplied at the required time, and for the interval necessary, tooperate the air cylinders for opening of the shroud and election of thebag at the proper stations.

The weighing hoppers are supported by any suitable structure not shown,above the rotating elements. As shown in Figure 4, station I is thefilling station. As the device is rotated between stations 2 and 3, theair cylinder I33 is actuated by air received from rotary valve I30through line I34 to cause the shroud to open, so that by the time itreaches station 3, it is completely open and the bag is ready fordischarge. At this point, air cylinder H0 is actuated to push the bagout of the shroud into chute I35, whence it travels to the disposalpoint. The shroud unit at station 4 is open, and at this point a bag isslipped over the fillin spout. It will be noted that the rotation of theunit is intermittent, so that during the period of time necessary tofill the unit in station I, there is plenty of time for the filled bagto be ejected at station 3 and for another bag to be placed over thefilling spout at station 4. After the bag is filled at station I, and asthe element to which the bag has been added at station 4 moves forwardinto station I, the split shroud is closed by the air cylinder, and bythe time the element reaches station I, it is ready to be filled. InFigure 1, at a and 901), a filled bag is shown as it is ejected from theopen shroud.

The operation As illustrated in Figure 1, three weighing hoppers and astorage hopper are provided. Two of the weighing hoppers are forobtaining rough weights, and likewise serve the purpose of deaeratingthe powder. The third hopper 22 is a final-weight hopper.

A powder such as carbon black, zinc oxide, or any other finely dividedbulk material, is placed in storage hopper I. Hopper 4 is evacuatedthrough line 5. Powder is drawn through valve 2, which is open. Sincehopper 4 is suspended by means of the knife edge I and the lever 8, andis conducted by flexible coupling to the storage hopper I and the lineI3, the arm 8 is free to act upon scale 8, the indicating pointer III ofwhich is set at 0 before the filling operation begins. As the hopperfills with powder, the arm III rotates and eventually contacts point 9,which closes an electrical circuit actuating a solenoid valve, causingvalve 2 to close as hereinbefore described. By the use of relays and atiming device, all well known, valve 2 can be kept closed until hopper 4is ready to receive another charge of powder. Scale 8 is set so that theamount of material weighed into hopper 4 is in excess of that which isultimately to be delivered to the container. This excess amount may varyfrom a few ounces to several pounds. The material having been deliveredto hopper 4, hopper I8, which is empty at this point, is evacuated, line5 is closed to vacuum and is relieved to atmospheric pressure; valve IIis opened and the contents of hopper 4 move into hopper I5. The scaleI3, actuated in a similar manner to scale 8, causes valve I I to closewhen the pointer strikes contact I8. Again the charge transferred tohopper I5 is slightly in excess of that to be ultimately delivered tothe container, although in general it may be more nearly the desiredamount than is that delivered to hopper 4. Hopper I5 is now released toatmospheric pressure by operation of the valve on line I9, and

7' hopper 22 is evacuated. Valve is opened, this operating in thefollowing manner to deliver an accurate, predetermined weight of powderto hopper 22.

The valves in Figure 2 are shown in position for drawing powder fromhopper I5 into hopper 22. Valve I9 is open, valve I8 is closed, valve Bis open, and valve A is closed. Hopper 22 is being evacuated, whichcauses powder to flow from hopper I5 into hopper 22 through the twoannular spaces shown in valve B. Hopper 22 is suspended as shown inFigure 1. When the weight of material in hopper 22 is sumcient such thatscale indicator 2! strikes contact point 26, the solenoid valvecontrolling line 68 is actuated, thereby applying air pressure to liner55 and causing it to inflate and close the outer large annular spacearound tube 60. This shuts off the major flow of powder. The point ofcontact is selected so that the weight of powder introduced into hopper22 is slightly less than that ultimately desired. This may be a matterof an ounce or several ounces, depending upon the size of the valve andthe amount of powder to be weighed. Powder continues to be drawn throughthe inner annular space around tube 66, and the scale indicator 25continues on as the weight of powder in hopper 22 increases until itcontacts point 21, at which point another solenoid valve is actuated toapply air pressure to line 62 and inflate rubber sleeve 88, thus closingthe valve and shutting ofl any further flow of powder from hopper I5.Hopper 22 now contains the exact amount of powder desired, and it isready for transfer to the ultimate container. The solenoid valvesreferred to may be of type such as V-5 of Skinner Chuck Company,Norwalk, Connecticut.

Valve 20 is then closed, and hopper 22 is released to atmosphericpressure. By this time one of the shrouds, containing an empty bag andready for filling, moves into position at station I.

Flanges 40 and 84 are clamped together as shown in Figure 5. Theinterior of the .shroud is evacuated by pulling a vacuum through lineII4, the three-way valve H8 being in the position shown in Figure 6.Until the shroud is substantially evacuated, valve 28 is kept closed. Asit is evacuated, the thin rubber tube I20 expands to seal the opening inthe corner of the bag. When the desired'vacuum has been reached (andthis is ordinarily within the range of about 15 to 20 inches ofmercury), valve 28 is opened, and the entire contents of hopper 22 arepulled into the bag. The sudden release of the contents into the bagcauses the material to pack. As previously pointed out, each of thehoppers is constructed as shown in Figure 2, so that the vibratingefl'ect of the inner liner prevents hangup of powder inside the hopper,so that this, together with the difference in pressure on the powder inthe hopper and within the bag, causes the complete delivery of anaccurately weighted amount of material to the container.

At this point valve H8 is rotated 90 counterclockwise to relieve thevacuum within the shroud, the air cylinder 86 is released, and the sealbetween flanges 48 and 84 is broken. Since the flexible coupling 2| isstretched when the flanges are clamped together, the contraction uponrelease allows flange 40 to swing clear of flange 84. In the rotarymachine above described, the hopper 22 is again filled with anaccurately weighed amount of powder while the dial is being rotated onequarter turn to bring the next unit into fllling position. The normalposition of flange 40 must be slightly above flange 85, to permit theshroud unit to move into filling position, and when it reaches thisposition, the air cylinder 86 may be actuated by any well known means tocause flange 48 to 'seal against flange 84 and gasket 85.

As previously mentioned, the operation of this filling apparatus causesa de-aeration of the powder. Many fine powders such as carbon black andthe like, are light and fluify due to the fact that air is entrappedbetween the particles. Such a condition is necessary to the free flow ofthe powder, but if this flufly powder is placed directly in a container,the container must be of sumcient volume to hold the desired weight ofaerated powder, which means that when the powder settles, the containerwill show considerable outage. This is undesirable.

In the present apparatus, each of the hoppers 4, I5 and 22 isconstructed as shown in Figure 2. The operation of this device has beenexplained above. The walls alternately present the corrugated patternshown in Figure 3 and then assume a substantially smooth inner surfacewhen the vacuum is released. This exerts a lateral squeezing or kneadingaction on the powder as it lies in the hopper. This aids in releasingentrained air in the powder. Since, as the-hopper is being filled, it isunder vacuum, the combined eilect of the vacuum and the kneading actionis to hasten the removal of air from the powder, and to cause it tobecome more and more compact. When the hopper is discharged, either tothe next hopper in line, or to the container, the body of the powder isdrawn downwardly and into the constriction at the valve, so as tofurther tend to squeeze out the air entrapped in the powder. ThlE, asthe powder progresses from one hopper to the next, the ultimate effectis to continuously knead the powder and to force the air out of it, andas a consequence, it becomes more and more compact; that is, theapparent density is reduced. By the time it reaches the container, thelargest portion of entrapped air has been removed, and as a consequence,a smaller container could be used than if the airfllled powder weredirectly introduced into the container. The movement of the withdrawnair is counter to the movement of the powder, so that it is continuouslyagitated, and this assures rapid and uniform flow without compacting thepowder to such an extent that it will bridge, or collect on the walls.

In Figures 7 to 10 is illustrated another and preferred form of shroud.This shroud comprises a plate I86, rigidly mounted on the supports I52,I53 which may be used in place of dial I24. A support I 81 is providedfor this purpose. Support I 31 is provided with an arm I38. Plate I86serves as one side of the shroud. Mounted on the arm I 88 is a rod I89,which passes through the bearings I48 attached to levers I, which inturn are attached to the movable member of the shroud I42 which formsthe remaining side thereof. The piston I48 of an air cylinder I44 ispivotally connected at I45 to cross bar I46, which extends between themembers I 4 I. The air cylinder is mounted on a bracket I46, which isattached to upports III. A three-way valve I I3 is attached to thestationary member I38, as previously described in connection with Figure6. A filling spout is attached to the flange '84 as a vertical sectionI41, forming an s at I48 and passing through one corner of thestationary member I 38 and thence downwardly to a spout I49. A

bag I", which is sewec aas previously described, and having a sealingfi'ap at the top corner, is slipped over the vertical spout-H9. In thiscase the bag lies on its side, resting on the bottom of the member I42,as may be seen by examination of the righthand portion of Figure 7, andFigure 9. The spout I49 may be provided with a sealing means I51, suchas that illustrated in connection with Figure 5. When the bag is filled,it assumes the position shown in Figure 9. When the shroud elementreaches station 3, the movable element I42 of the split shroud is thrustoutwardly by actuating air cylinder I, and the bag drops downwardly asshown in Figure onto a chute or conveyor belt, to be removed to storage.

As illustrated, two elements of a four-shroud unit are shown in Figures7 and 8. It is possible to construct the apparatus with only threeunits, and hence three stations, namely, a filling station, a dumpingstation, and a bag-placement station. As previously mentioned, this canalso be constructed as a single-station machine. The multiple-stationmachines provide for greater fill-' ing capacity than can be realizedwith a singleunit machine. The various operations are synchronized bysuitable timing devices, so that it is automatic. Generally the bags areplaced in position by hand. The containers can be positioned for fillingby automatic means, which will vary depending upon the type andconstruction of the container, appropriate modifications being made forthis purpose. The machine can also be designed to operate with a largernumber of units and having more than one filling station.

The invention is not limited to the exact embodiments illustrated.

I claim as my invention:

1. A powder filling machine which comprises a first weighing hopper, apowder inlet valve, 2. powder outlet valve, means for determining thenet weight of powder within said hopper, means for evacuating the hopperto draw powder into the hopper from a supply source when the inlet valveis open, means for closing the inlet valve when a predetermined amountof powder has been added, means for restoring said hopper to atmospheriepressure, means for opening the outlet valve, a second weighing hopper,a conduit connecting the outlet valve to said second weighing hopper inseries, means for determining the net weight of powder within saidsecond hopper, means for evacuating the second hopper to draw powderfrom said first hopper, means for closing the outlet valve of the firsthopper when a predetermined weight of powder is introduced into thesecond hopper, means for releasing said second hopper to atmosphericpressure, and vacuum means for introducing the weighed contents of saidsecond hopper into a container.

2. The apparatus of claim 1 wherein the outlet valve from the firsthopper comprises a relatively large passageway and a relatively smallpassageway for powder, means for opening and closing the largepassageway, and independent means for opening and closing the smallerpassageway.

3. The apparatus of claim 1 wherein the means for filling the containercomprises a spout capable of being introduced into a flexible container,a container shroud, means for evacuating the shroud, means for releasingthe vacuum in the shroud, the walls of said shroud being made up ofsections, at least one of which is stationary and at least one of whichis movable, means for moving the movable section to open the shroud,

whereby a container may be removed therefrom or placed therein.

4. The apparatus of claim 1 comprising a means for mounting said hoppersin a stationary position, said filling means comprising a plurality ofcontainer shrouds mounted for intermittent rotation on a dial, saidshrouds being vertically divisible into sections, one section beingstationary, said section having a filling spout extending therethroughand having means for joining and means for releasing it, from fillingrelationship with the outlet of the second hopper, means for moving thesecond section of the shroud away from the first to provide access tothe interior of the shroud for removing and replacing containerstherein, means for moving the movable sections back into gas-tightrelationship with the stationary section, means for intermittentlymoving each of said shrouds into filling relationship with the outlet ofthe second hopper, and means for removing filled containers from theshroud after said shroud has been moved out of filling relationship withsaid hopper.

5. A filling machine comprising a plurality of weighing hoppersconnected in a series by conduits, valves in the conduits, an inletvalve connectible with a source of powder supply in the first hopper inthe series, an outlet valve in the last hopper of the series, saidhoppers being fiexibly connected to permit weighing of the contents ofeach hopper, said hoppers being suspended on balance arms, weighingmeans actuated by said arms, means for evacuating each of said hoppersindependently of the others, means for releasing the vacuum within eachof said hoppers independently of the others, means for opening theoutlet valve to the first hopper to permit intro- ;duction of powderfrom said supply source when said first hopper is evacuated, means forclosing said inlet valve when a predetermined weight of powder has beenadmitted, means for opening the valve in the conduit between the firsthopper and the second hopper to pass the powder from the first hopperinto the second hopper, means for closing said valve when apredetermined weight of powder has been introduced into the secondhopper, each of said hoppers in the series being similarly provided fortransfer of a weighed amount of powder from one hopper to the next inthe series, and vacuum means for delivering a weighed amount of powderthrough the outlet valve of the last hopper in the series to acontainer.

6. The apparatus of claim 5 wherein the valves comprise an inflatablemember, means for infiating said member to close the valve, and vacuummeans to deflate the member and open the valve.

7. A powder filling machine comprising at least two gross-weightweighing hoppers connected in series and an accurate-weight weighinghopper, vacuum means for passing a predetermined approximate weight ofpowder into the gross-weight hopper from a supply source, vacuum meansfor rapidly passing the bulk of the contents of the gross-weight hopperinto the accurate-weight hopper, means for thereafter reducing the rateof powder flow, means for stopping powder flow when an accuratepredetermined weight has been collected in the accurate-weight hopper,and vacuum means for rapidly passing the weighed contents of theaccurate-weight hopper into a container.

8. A powder filling machine which comprises a first weighing hopperattachable to a powder supply source, an inlet valve to the hopper, afirst first hopper when the valve means is opened, and

vacuum means for discharging the net contents of the second hopper intoa container.

References Cited inthe file or this patent UNITED STATES PATENTS NumberNumher Name Date Stearns May 3, 1898 Fasting Sept, 3, 1912 Wright Oct.14, 1924 Ryan Nov. 30, 1937 Cave Apr. 26, 1938 Ryan Nov. 29, 1938 BorchAug. 22, 1939 Rogers Apr. 27, 1943 Compa May 13, 1947 De Cew Oct. 16,1951 FOREIGN PATENTS Country Date Aug. 29, 1940

